The cost for production of energy in wind power plants accrues from initial investments in the plant and maintenance costs. Components included in the wind power plants are exposed to wear, resulting from load with a large variety during the operation of the power plant. This in particular applies to components that are subject to fluctuating or oscillating loads such as gearboxes and transmission elements. Fluctuating or oscillating loads are prone to result in fatigue of the components. In order to ensure that an initial investment in a wind power plant generates power at as low cost as possible it is a necessity to have a maintenance schedule for the plant, such that the operation of the wind power plant may be safeguarded. Current maintenance practice for wind farms consists of scheduled maintenance and unscheduled maintenance.
In order to improve the possibility of accurately scheduling maintenance turbine condition monitoring systems have been suggested. With the installation of a turbine condition monitoring system, early detection of the component failure is possible. An example of a system for monitoring gearbox components is described in EP1930855.
EP1930855 disclosures a gearbox life estimation system which will estimate the remaining life of the gearbox based on the operational load data measured through sensors. Individual load on components are calculated. From the individual loads an assessment of the remaining life as a real time estimate is obtainable. A maintenance schedule may be set using the information about the calculated remaining life. Even though the method described in EP1930855 improves the capability of deciding appropriate maintenance intervals, further improvements are desirable in order to further reduce the risk for component failure and to reduce the risk of a need for unscheduled maintenance.
Unscheduled maintenance usually happens when a component failure is detected and repair or replace actions have to be taken. The cost of unscheduled maintenance is one of the biggest contributors for the turbine operation and maintenance cost.